ChangeNOW.io has bad reputation in Bitcointalk forum and they have never resolved it completely.

Their representative at the forum: ChangeNOW has lot of negative trust feedback and they have active scam accusations

2,5 BTC ($100K) SCAM Changenow exchange. I did not read details but if you intend to use their service, you should read it.

In addition, what you do is convert your BTC to ETH, not swap. Swap is on decentralized exchanges, with tokens on a same network (same blockchain). Or did you swap WBTC to ETH? Remember WBTC is not Bitcoin, it is only a derivative token.